1. Simon Hyun, Brett Douglas, Eldad Perahia, Dave Petsko
Month 2000
doc.: IEEE /846r0
November 2003
Direct Path to Multipath Ratio and RMS Delay Spread Measurements in an Office and a Lab Environment
Simon Hyun, Brett Douglas, Eldad Perahia, Dave Petsko
Cisco Systems, Inc.
Perahia et. al., Cisco Systems, Inc.
John Doe, His Company

2. Background Information
November 2003
Background Information
K-factors are defined in the N Channel Models. The models for K-factors can be compared to measured data by calculating a Direct Path to Multipath Ratio (DPMPR) – The ratio of energy in the direct path (first tap) to the sum of the energy from all Multipath samples (all other taps).
In N, the models have the following (DPMPR).
Model B -> 9.16 dB
Model C -> 1.09 dB
Model D -> dB
Perahia et. al., Cisco Systems, Inc.

3. Direct Path to Multipath Ratio Calculation
November 2003
Direct Path to Multipath Ratio Calculation
Perahia et. al., Cisco Systems, Inc.

4. November 2003
RMS Delay Spread
The N Channel Models have increasing RMS delay spread
Model B: 15nsec
Model C: 30nsec
Model D: 50nsec
Perahia et. al., Cisco Systems, Inc.

5. Office Data Acquisition
November 2003
Office Data Acquisition
2ft y1 z1 a1 b1 c1 d1
31 ft. y2 z2 a2 b2 c2 d2
29 ft. y3 z3 a3 b3 c3 d3
27 ft. y4 z4 a4 b4 c4 d4
25 ft.
2ft
Aisle way RX
(Orientation: | )
Dipole antennas
Aisle way
Pillar
Path Obstruction
(5-employee cube)
Aisle way
Path Obstruction
(5-employee cube)
25ft
Perahia et. al., Cisco Systems, Inc.

6. Lab Data Acquisition November 2003 Obstruction 2ft y1 z1 a1 b1 c1 d1
Benchtop
2ft y1 z1 a1 b1 c1 d1 y2 z2 a2 b2 c2 d2 y3 z3 a3 b3 c3 d3 y4 z4 a4 b4 c4 d4 RX
(Orientation: | )
Dipole antennas
2ft
Path Obstruction
(test bench / equipment)
Path Obstruction
(test bench / equipment)
25ft
Perahia et. al., Cisco Systems, Inc.

7. DPMPR Distribution in an Office: LOS
November 2003
DPMPR Distribution in an Office: LOS
Min: dB
Mean: -1.5 dB
Max: 5.7 dB
Perahia et. al., Cisco Systems, Inc.

8. RMS Delay Spread Distribution in an Office: LOS
November 2003
RMS Delay Spread Distribution in an Office: LOS
Min: 19.6 nsec
Mean: 33.7 nsec
Max: 46.9 nsec
Perahia et. al., Cisco Systems, Inc.

9. DPMPR Distribution in a Lab: LOS
November 2003
DPMPR Distribution in a Lab: LOS
Min: -7.7 dB
Mean: .6 dB
Max: 5.4 dB
Perahia et. al., Cisco Systems, Inc.

10. RMS Delay Spread Distribution in a Lab: LOS
November 2003
RMS Delay Spread Distribution in a Lab: LOS
Min: 11.8 nsec
Mean: 18.5 nsec
Max: 24.2 nsec
Perahia et. al., Cisco Systems, Inc.

11. DPMPR Distribution in an Office: NLOS
November 2003
DPMPR Distribution in an Office: NLOS
Min: dB
Mean: -5.1 dB
Max: 3.3 dB
Perahia et. al., Cisco Systems, Inc.

12. RMS Delay Spread Distribution in an Office: NLOS
November 2003
RMS Delay Spread Distribution in an Office: NLOS
Min: 28.7 nsec
Mean: 37.5 nsec
Max: 48.2 nsec
Perahia et. al., Cisco Systems, Inc.

13. DPMPR Distribution in a Lab: NLOS
November 2003
DPMPR Distribution in a Lab: NLOS
Min: dB
Mean: -6.9 dB
Max: 1.6 dB
Perahia et. al., Cisco Systems, Inc.

14. RMS Delay Spread Distribution in a Lab: NLOS
November 2003
RMS Delay Spread Distribution in a Lab: NLOS
Min: 17.3 nsec
Mean: 23.2 nsec
Max: 31.8 nsec
Perahia et. al., Cisco Systems, Inc.

15. November 2003
Conclusions
The measurements reflect propagation conditions in a small office. This corresponds to n Channel Model C with a DPMPR of 1.09 dB and RMS delay spread of 30nsec.
LOS measurements results:
Mean DPMPR’s: -1.5 and -0.6 dB; close agreement with Model C.
Mean RMS delay spread measurements: 33.7 and 18.5 nsec; similar to model C.
NLOS measurements results:
Mean DPMPR’s: -5.1 and -6.9 dB; very different than Model C.
Mean RMS delay spread measurements: 37.5 and 23.2 nsec; similar to model C.
We could use two Model C’s, Model CL with a K-factor of 2 or 3 dB for LOS channels. Model CN with a K-factor of (–inf) dB for NLOS channels.
The NLOS mean DPMPR measurements match very closely to Model D. An alternative which results in fewer channel models would be to use Model C for LOS small office conditions and Model D for small office NLOS conditions. Though the measured RMS delay spread for NLOS conditions is higher than LOS conditions, it is still smaller than that for Model D. This would need to be resolved.
Perahia et. al., Cisco Systems, Inc.